First time to track in 12 years with my '87 GN

[trbogn]

I first bought my 87 GN when I was 18 and have had it for the past 14 years. I frequented the track for the first few years when I got the car and had it really dialed in with race trim (see sig). I finally finished med school, residency and fellowship and now finally have time to enjoy my GN. After all of the maintenance stuff was sorted out (after only putting about 50 miles on it during past 12 years) I headed to the track.

I was more concerned about just getting a good baseline street tune. Was running a TT 93 octane street chip and 100 octane unleaded gas to be safe (stock cat in place). It was 60* out.

Tonight car had stock catalytic converter installed (from my last emissions test in like 2002), I wasn't able to install my test pipe or run an open dump before heading to the track. I know this probably killed my performance.

First pass was 13.3 @101 with 1.88 60". 18 pounds, unlocked stock TC, 44psi line off FP, 0.9 knock, O2 in 3rd gear at 710.

Second pass was 13.5 @ 100 with 2.1 60". 18 pounds. I cranked up FP to 46psi to get my O2 up. O2 was 720.

I increased my FP further up to 48psi to try and get my O2 up in the 750 range, but it was still in the 720-730 range.

Since I didn't have any significant knock readings I tried turning the boost up a bit (2 turns on my cut stock wastgate) and my boost was way out of control up to 23-24 pounds with 5-6 degrees knock.

I finally got the boost back down to the 17-18 pound range and the car clicked off another 13.3 @ 102.

One my last pass I did the paper clip trick and locked the converter. 13.3@104 with 2.3 60" time.

So I have a few questions.
-Are the O2 readings of low 700's concerning? Even at 48psi line off FP I was in the low 700's. Time to upgrade the stock injectors? The car has the hotwire kit and aftermarket fuel pump. I have been over 110 mph with these stock injectors in the past without issue.

-How much mph gain do you think would be seen by installing the test pipe or a dump? I have a 2.5" high flow cat back exhaust. I know that the stock cat robbed me of at least 2-3 mph.

-My rear airbags would not hold any air. They were deflated for almost 10 years. All the fittings are intact. Guess the airbags just dry out and crack over time?

-I guess I am just concerned that my mph was so low. But I guess the car ran pretty good for first time out after all this time.

 

[trbogn]

Just curious. Do these numbers make sense?

12.39 @ 111 in race trim. 110 octane, 32* timing race chip, 22 pounds boost, open dump, locked converter.
13.3 @104 in street trim. 93 octane TT chip (18* timing), 18 pounds boost, stock cat in place, locked converter.

Maybe I just didn't realize that there would be such a huge difference between race and street trim.

 

[baby6]

02s seem to be pretty low, as to why im not sure. those numbers seem pretty accurate 1/4 wise, though. fuel pressure wont necessarily bring 02s up, maybe turn up the injector duty cycle a little at WOT, via the turbotweak chip? did the 02s drop the higher the rpms went?

I have always had a similar issue with my car, 02s going from 800 at the bottom of third reaching the mid 700s at the top. I have just learned to tune for no knock, the narrowband 02 isnt the most accurate.

 

[earlbrown]

With that much age, you really need to swap out the timing chain, possibly change the valve springs, get rid of that cat, and consider a few more modern upgrades. I'd highly recommend a modern chip with a new set of matching injectors along with a translator coupled to a modern MAF.

Bonus points if you get a powerlogger and a wideband. They're MUCH MUCH cheaper now than they were 12 years ago.

 

[Bescurred]

Adjusting the FP at the rail isn't going to make your 02's go up much if any. You have to do it via the chip.

I'd do what Earl said. Then get an exhaust. Figure out how to launch the car and once your ready start upping the boost once you get some octane.

Several years ago I went low 12s on pretty much a stock set up. You'd be surprised what a stock car can do with the boost in the low 20s and a good sixty foot.

 

[trbogn]

Thank you for the replies.

baby 6. the O2s were pretty stable entire 3rd gear. Hovered in low 700s. I forgot that I can add more fuel via the TT93 chip. Something I will play with in the future.

Bescurred. Thanks for the info. I just assumed adjusting the FP at the rail would raise the O2 readings, guess that isn't the case. I used to go low 12s regularly, but that was 12 years ago with the car sitting for the past 10 years or so. Just trying to get all the cobwebs out.

I went back to the track tonight. The fuel issues seemed to be better.

I took the catalytic converter off and ran straight off the downpipe. Put in 7 gallons of 112 race gas.

Pass 1. TT 93 chip, 15 pounds boost, 46 FP. Ran 13.4 @103 with 2.1 60". 0 knock. O2s were 760-770 in third.

Pass 2. I abandoned tuning the car for the street and decided to drop in my old Jay Carter 110 octane chip (32* timing). Locked the converter with a paper clip. (same setup I ran 10+ years ago).
Ran 13.3 @110 with terrible 2.4 60". 24 pounds boost, 46FP. 0 knock. O2 in the 740 range. Crazy thing is that I only tightened my wastegate rod 1 turn on this first pass with the race chip, but the boost jacked up to 24 pounds (from 15). Is this normal? Seems like a huge jump with just changing the chip.

I only made 2 passes tonight, pretty much wasting the $60 in racegas.

The 110 mph pass was scary. The rear end was squatting/wiggling all over the place from like 40-80mph (no tire spin, just unstable). I decided I didn't want to risk another pass without some suspension attention. My suspension is all stock except a new front sway bar, rear seat braces and under hood braces. Air bags not working/deflated. BFG 275/50/15 at 18 psi on stock rims. When I last raced like 10 years ago my car did not act like this, I remember it being pretty stable during passes. Guess after 10 years of sitting the bushings/shocks/springs have gone bad?

I need to address the rear suspension. What would be a good maintenance overhaul? Not looking for all out drag suspension, but want to bring it up to snuff and be safe/stable. Upper and lower control arms? New bushings? How much doers something like this cost for a shop to install it all?

Thanks again for all the info.

 

[garyk1970]

I agree with Earl on the point of the valve springs....they are a pita to replace, but my car didn't pick up mph until I changed them....
Also modern chip, I bet the fuel pump is weak, or hot wire kit.
A data logger will help analize everything and make educated adjustments


My Ts rear started swaying left to right at high speeds....interested in hearing some advice too.

 

[Razor]

I would start with a new fuel pump.

 

[we4Mateo]

Razor beat me to it. Your pump probably isn't keeping up thus you aren't seeing results from fuel pressure changes. That wb probably isn't going to read right with all that lead for long and it doesn't show much anyway. Get a lead tolerant wb like earl suggested and tune.

 

[TexasT]

Are the tires new or the 10year old ones? If ten year old they are maypops and you really should seriously consider replacing them before they shed a cap or worse.
Dried out bushings probably have a lot of play, look at replacement and maybe a swaybar upgrade if you have the coin. I like a stock spring for weight transfer but with your 60' you should probably look at the front with some shocks and disconnect sway bar. Just some sticky tires should get you 1.8 or so 60' and should get you to the 12.40s if your fuel pump could keep up. Hot wire if it isn't already. New pump and possibly the hanger. Drill out that hanger for better flow. New fuel filter for sure. Injectors cleaned or replaced(big talk for me as I'm running stockers at the present).

Posted from the TurboBuick.Com mobile app

 

[we4Mateo]

I've pulled a 1.54 60' with the front swaybar still connected off the foot brake on skinny 9" MT ET Streets. Hellwig rear swaybar and boxed lowers only.

 

[trbogn]

TexasT. The tires are old, probably 12 years old or so. They only have about 1000 miles on them. I am not so much concerned with 60" times as I am with safety. This thing got real squirrelly on the 110 mph pass. Definately did not feel right.....like the rear end was wobbling back and forth.

Here are photos of my external in-line fuel pump. Not sure the brand or model. Any ideas? The prior owner installed it to a switch under the dash. Not sure why you would want to turn the fuel pump on and off? With ignition on, engine off, you can hear the fuel pump fairly loud. I do not know if the in-tank pump is stock or not.

 

[trbogn]

Did stock GNs have an inline fuel pump in this location or was this added by previous owner?

 

[TexasT]

Secondary external fuel pump was the rage way back when(my car still has a Bosch 44 bolted to the trunk floor above the axle), but that was then, this is now. Plenty of intank pumps that can feed your power. If I was you (and I did), I would get a decent pump and plumb around that relic. It has probably become a restriction. Plenty of our vendors can steer you to the right pump(nick, or full throttle or one of our other fine vendors of your choosing.)
Get a hot wire kit when ordering and do it all at once. The next trip to the track after that should have you at the 110mph consistantly.
And replace those tires. Good for burnouts but just not worth bending you car up for $400-600.
Keep us up on your progress.

Posted from the TurboBuick.Com mobile app

 

[trbogn]

Thanks. I will likely do what you said and install an intank pump with hotwire kit and bypass the inline secondary pump.

The previous owner had the power supply to the inline pump coming from the ign slot in the fuse box under the dash. I am assuming there is not a hot wire kit then.

 

[trbogn]

Sorry for the dumb questions.

I am trying to see if there is a hotwire kit installed already (maybe prior owner had hotwired intank pump and an in-line pump, know knows). All the kits have a connection to back of alternator. Here is pic of mine. Is there anything else that is connected to the alternator here that is stock?

 

[trbogn]

On inner fender wall, drivers side. Not sure if this is a hotwire component. The one on the right says Applied Technology and Research, which may be part of old car alarm previous owner had installed (I removed most of it over 10 years ago) The middle one doesn't look stock either.

 

[earlbrown]

You don't have a hotwire kit. The secondary pump is most likely there to fortify the weak stock pump (while also being underpowered).

My guess is you still have stock (width) rims and that's the reason for the squirreliness. If they're Radial T/A's they do that on stock rims. The sidewalls are just pulled in to far.


On the pic of your relay bank, remove the large one with two plugs, walk to your backyard and throw it as far as you can. Then go pick it up and throw it again. If by some chance it doesn't fall in to a 10,000 foot crevice right into the gates of hell, smash it with a hammer and throw it again. You do have a pic of a non stock blue wire but I can't tell what color factory wire it plugs into. It might be a high speed fan override but that wire would have to be extended to reach that far.

You do have an ATR something or another that looks like it's plugged into the stock harness. I don't recall them making replacement relays though.


Looks like you need to pretend like you just bought this car and no nothing about it. Time for a new fuel pump, toss the secnod one, do the hangar mods, new valve springs, rocker buttons, timing chain, do the oil pump mods while you're there, injectors, chip and a translator with a modern MAF, all new vacuum hoses and check valves.....

THEN find out what the car is hiding from you.

www.discounttiredirect.com has a great deal on Cooper Cobra's right now. I got a pair of 295's and a pair of 235's to my door for $505

 

[baby6]

Earl, what is that relay you want him to throw so bad? Lol

 

[earlbrown]

Fan delay relay.

Also known as ''turn the fan on in the middle of the night and kill your battery" relay. or sometimes the "I have the oddesst running condition and I can't figure it out even after throwing $100's in parts at it" relay.